A plan of operation may be amended from time to time at the request of the corporation or the commission. Amendments proposed by the corporation shall be submitted in writing to the commission, and the commission shall approve or disapprove of such proposed amendment within 30 days of such proposed amendment’s having been submitted. No prepared amendment shall be effective unless the same shall have been approved by the commission and ordered by the commission incorporated in the plan of operation. The commission may at any time propose amendments to a plan of operation. A corporation may request a hearing concerning the rejection by the commission of an amendment proposed by such corporation or the proposal of an amendment by the commission by filing a request therefor with the commission, in writing, within five days of receipt of notification of the commission’s action to which the corporation takes exception.